Biofilm Formation and Susceptibility to Polymyxin B by a Highly Prevalent Clone of Multidrug-Resistant Acinetobacter baumannii from a Mexican Tertiary Care Hospital

Background:Acinetobacter baumannii has emerged as a major cause of hospital-associated infections with increased morbidity and mortality among those affected. Methods: A total of 85 isolates of a highly prevalent multidrug-resistant clone, identified during the period 2007-2011, were analyzed for biofilm formation on a polystyrene surface. The minimal inhibitory concentration was determined by the Sensititre System, the agar disk diffusion method and then read by means of the BIOMIC system and serial dilutions on Müller-Hinton agar. Results: In this study, covering a period of 5 years (2007-2011), we demonstrate that a particular clone emerged as the most prevalent, with an associated lethality of 28.2%. We demonstrate that 92.9% of strains corresponding to this clone are biofilm producers. Our results also demonstrate that all isolates were 100% susceptible to polymyxin B. Conclusion: Our study suggests that the high prevalence and lethality of this multidrug-resistant clone of A. baumannii and its persistence over close to 5 years in a Mexican tertiary hospital environment can be explained in part by the ability of these clinical isolates of A. baumannii to form biofilms.

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TO STUDY ANTIBIOTIC SENSITIVITY PATTERN OF NONFERMENTATIVE GRAM NEGATIVE BACILLI FROM VARIOUS CLINICAL SAMPLES IN A TERTIARY CARE HOSPITAL, JAIPUR.

International Journal of Medical and Biomedical Studies ◽

10.32553/ijmbs.v4i5.1132 ◽

2020 ◽

Vol 4 (5) ◽

Author(s):

Kirti Hemwani ◽

P. S. Nirwan ◽

Preeti Shrivastava ◽

Abhiraj Ramchandani

Keyword(s):

Tertiary Care ◽

Antibiotic Sensitivity ◽

Polymyxin B ◽

Hospital Environment ◽

Diffusion Method ◽

Clinical Samples ◽

Care Hospital ◽

Pathogenic Potential ◽

Gram Negative ◽

Sensitivity Pattern

Background: Nonfermentative gram negative bacilli (NFGNB) frequently considered as commensals or contaminants but the pathogenic potential of nonfermenters has been proved beyond doubt. They are resistant to commonly used antimicrobials. Aim: This study was undertaken to identify the nonfermenters isolated from various clinical samples and to know their Antibiotic sensitivity pattern. Materials and Methods: The present study was carried out on 150 strains of Nonfermenters isolated from 1200 various non repetitive clinical samples received in Department of Microbiology, NIMS Jaipur. Nonfermenters were identified using a standard protocol and their antibiotic susceptibility testing was performed with the help of the modified Bauer disc diffusion method. Results: Out of 150 nonfermenters isolated, Pseudomonas aeruginosa was the most common isolate 134 (89.33%) followed by Acinetobacter baumannii 16 (10.67%). Among all clinical samples Pus and Wound Discharge yield maximum isolates of NFGNB i.e. 54 (36%) % followed by sputum (39.0%). Most sensitive drug against NFGNB was Polymyxin-B (100%) followed by Imipenem (86 %) and Amikacin (71.33 %). Conclusion: Nonfermenters have a great potential to survive in a hospital environment so implementation of antibiotic stewardship programs and strict infection control practices will be required to prevent or slow down their emergence and spread. Keywords: Nonfermenters, Polymyxin-B, Pseudomonas, Acinetobacter.

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Phenotypic and genotypic characterization of multidrug-resistant isolates from patients with catheter-associated urinary tract infection in a tertiary care hospital

Journal of Laboratory Physicians ◽

10.4103/jlp.jlp_22_19 ◽

2019 ◽

Vol 11 (03) ◽

pp. 206-211

Author(s):

Jaison Jayakaran ◽

Nirupa Soundararajan ◽

Priyadarshini Shanmugam

Keyword(s):

Urinary Tract ◽

Tertiary Care Hospital ◽

Tertiary Care ◽

Carbapenem Resistance ◽

Multidrug Resistant ◽

Diffusion Method ◽

Care Hospital ◽

Disk Diffusion Method ◽

Carbapenem Resistant ◽

Tract Infections

Abstract INTRODUCTION: Urinary tract infections (UTIs) remain as the most common infection. Catheter-associated (CA) UTI can lead to bacteremia and thereby is the leading cause of morbidity and mortality in hospitalized patients in our country. AIMS AND OBJECTIVES: This study aims to check the prevalence of CAUTI and study the phenotypic and genotypic characters of the multidrug-resistant organisms in a tertiary care hospital, with special reference to NDM-1 and OXA-23. MATERIALS AND METHODS: A total of 231 urine samples from patients with CA-UTI in different wards in a tertiary care hospital over a period of 3 months between June and August 2018 were collected and processed following the standard protocol. Antibiotic susceptibility tests were performed by disk-diffusion method. Modified Hodge test (MHT) was done to isolate carbapenem-resistant isolates, and polymerase chain reaction was done to detect NDM-1 and OXA-23. RESULTS: Out of 231 samples, 101 samples yielded significant growth. These 38 samples were Gram-negative bacilli which were resistant to carbapenems. Out of the 38 which showed carbapenem resistance, 23 were MHT positive. Out of the 23 MHT-positive isolates, 8 (21.05%) were positive for NDM-1 gene and only 1 (2.6%) was positive for the OXA-23 gene. CONCLUSION: This study has shown that carbapenem-resistant isolates from all the CA urinary tract-infected patients were 52.77% and most of them were Klebsiella. About 21% of them harbored the NDM-1 gene whereas only 2% had the OXA-23 gene. There has been an alarming increase in the spread of carbapenem resistance.

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Drug Resistance and Biofilm Production among Pseudomonas aeruginosa Clinical Isolates in a Tertiary Care Hospital of Nepal

Nepal Medical College Journal ◽

10.3126/nmcj.v21i2.25109 ◽

2019 ◽

Vol 21 (2) ◽

pp. 110-116

Author(s):

Rajani Shrestha ◽

N. Nayak ◽

D.R. Bhatta ◽

D. Hamal ◽

S.H. Subramanya ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Drug Resistance ◽

Biofilm Formation ◽

Tertiary Care ◽

Clinical Problem ◽

Multidrug Resistant ◽

Clinical Isolates ◽

Diffusion Method ◽

Care Hospital ◽

Microbiological Methods

Clinical isolates of Pseudomonas aeruginosa often exhibit multidrug resistance due to their inherent ability to form biofilms. Drug resistance in Ps. aeruginosa is a major clinical problem, especially in the management of patients with nosocomial infections and those admitted to ICUs with indwelling medical devices. To evaluate the biofilm forming abilities of the clinical isolates of Ps. aeruginosa and to correlate biofilm formation with antibiotic resistance. A total of 90 consecutive isolates of Ps. aeruginosa obtained from various specimens collected from patients visiting the Manipal Teaching Hospital, Pokhara, Nepal between January 2018 - October 2018 were studied. Isolates were identified by standard microbiological methods. Antibiotic susceptibility testing was performed by Kirby-Bauer disc diffusion method. All the isolates were tested for their biofilm forming abilities by employing the tissue culture plate assay. Of the 90 Ps. aeruginosa isolates, maximum i.e 42 (46.6%) were from patients in the age group of > 50 years. Majority (30; 33.3%) of the isolates were obtained from sputum samples. However, percentage isolation from other specimens like urine, endotracheal tube (ETT), pus, eye specimens and blood were 18.9%, 16.7%, 16.7%, 7.8% and 6.7% respectively. All the isolates were sensitive to polymixin B and colistin, 91.1% of the organisms were sensitive to imipenem, and more than 80% to aminoglycosides (80% to gentamicin, 83.3% to amikacin). A total of 29 (32.2%) organisms were biofilm producers. Maximum numbers of biofilm producing strains were obtained from ETT (8 of 15; 53.3%), pus (8 of 15; 53.3%) and blood (2 of 6; 33.3%) i.e from all invasive sites. None of the isolates from noninvasive specimens such as conjunctival swabs were biofilm positive. Significantly higher numbers of biofilm producers (23 of 29; 79.3%) were found to be multidrug resistant as compared to non-biofilm (6 of 61; 9.8%) producers (p=0.000). Ps. aeruginosa colonization leading to biofilm formation in deep seated tissues and on indwelling devices is a therapeutic challenge as majority of the isolates would be recalcitrant to commonly used antipseudomonal drugs. Effective monitoring of drug resistance patterns in all Pseudomonas clinical isolates should be a prerequisite for successful patient management.

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Gram-negative bacilli causing infections in an intensive care unit of a tertiary care hospital in Istanbul, Turkey

The Journal of Infection in Developing Countries ◽

10.3855/jidc.4277 ◽

2014 ◽

Vol 8 (05) ◽

pp. 597-604 ◽

Cited By ~ 1

Author(s):

Seniha Senbayrak Akcay ◽

Asuman Inan ◽

Simin Cevan ◽

Ayse Nilufer Ozaydın ◽

Naz Cobanoglu ◽

...

Keyword(s):

Intensive Care Unit ◽

Intensive Care ◽

Tertiary Care ◽

Multidrug Resistant ◽

Diffusion Method ◽

Care Hospital ◽

Chi Square ◽

Disk Diffusion Method ◽

Gram Negative ◽

E Coli

Introduction: This study aimed to demonstrate the changing epidemiology of infecting microorganisms and their long-term resistance profiles and to describe the microbiological point of view in anti-infective management of intensive care unit (ICU) patients. Methodology: A total of 5,690 isolates of Gram-negative bacilli were included in this study. Antibiotic susceptibility was tested using the disk diffusion method and Vitek 2 system. Chi-square tests were used for hypothesis testing. Results: The most frequently isolated organisms were A. baumannii (37.3%), P. aeruginosa (30.3%), Enterobacter spp. (10.4%), E. coli (10.4%), and Klebsiella spp. (8.9%). A. baumannii was the most frequently isolated organism from the respiratory tract (43.4%); the susceptibility rates for imipenem and meropenem decreased to 7% and 6% (p < 0.0001), respectively. The percentage of multidrug-resistant (MDR) A. baumannii isolates continuously increased from 18.7% in 2004 to 69% in 2011 (p < 0.0001), whereas MDR P. aeruginosa isolates increased from 1.5% to 22% (p < 0.0001). Carbapenem-resistant Klebsiella isolates emerged in 2010 and increased to 20% in the next year. The rates of ESBL-producing Enterobacteriaceae in the ICU was very high in 2011 – 50% for E. coli and 80% for Klebsiella strains. Conclusion: The most common isolated Gram-negative bacillus in our study was A. baumannii and that the prevalence of MDR isolates has increased markedly over. Accordingly, the comparison of antibiotic resistance of other pathogens in 2004 and 2011 displayed an increasing trend. These data imply the urgent need for new and effective strategies in our hospital and in the region.

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Prevalence of Multidrug-resistant and Carbapenemase-producing Klebsiella Pneumoniae and Pseudomonas Aeruginosa Isolates in Tertiary Care Hospital in Kathmandu, Nepal

Nepal Medical College Journal ◽

10.3126/nmcj.v23i4.42209 ◽

2021 ◽

Vol 23 (4) ◽

pp. 290-296

Author(s):

Rojina Darnal ◽

Mehraj Ansari ◽

Ganesh Rai ◽

Kul Raj Rai ◽

Shiba Kumar Rai

Keyword(s):

Pseudomonas Aeruginosa ◽

Klebsiella Pneumoniae ◽

Tertiary Care Hospital ◽

Tertiary Care ◽

Multidrug Resistant ◽

Diffusion Method ◽

Clinical Samples ◽

Resistant Bacteria ◽

Care Hospital ◽

Disk Diffusion Method

Carbapenemases are the enzymes that catalyze β–lactam groups of antibiotics. The carbapenemase producers are resistant to β–lactam antibiotics and are usually multidrug-resistant bacteria challenging widely used therapeutics and treatment options. Therefore, the detection of carbapenemase activity among clinical isolates is of great therapeutic importance. We aimed to study the MDR and carbapenemase-producing Klebsiella pneumoniae and Pseudomonas aeruginosa isolated from various clinical samples at a tertiary care hospital in Nepal. A total of 3,579 clinical samples were collected from the patients visiting the Department of Microbiology, B&B Hospital, Gwarko, Lalitpur. The samples were processed to isolate K. pneumoniae and P. aeruginosa and then subjected to antibiotic susceptibility testing (AST) by the Kirby-Bauer disk diffusion method. Phenotypic detection of carbapenemase activity was performed in the imipenem-resistant isolates by the modified Hodge test (MHT). Of the total samples, 1,067 (29.8%) samples showed significant growth positivity, out of which 190 (17.3%) isolates were K. pneumoniae and 121 (11.3%) were P. aeruginosa. Multidrug resistance was seen in 70.5% of the K. pneumoniae isolates and 65.3% of the P. aeruginosa isolates. Carbapenemase production was confirmed in 11.9%, and 12.2% of the imipenem-resistant K. pneumoniae and P. aeruginosa isolates, respectively, by the MHT. This study determined the higher prevalence of MDR among K. pneumoniae and P. aeruginosa; however, carbapenemase production was relatively low.

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Prevalence of multidrug-resistant and extended-spectrum beta-lactamase producing Gram-negative isolates from clinical samples in a tertiary care hospital of Nepal

Tropical Medicine and Health ◽

10.1186/s41182-021-00313-3 ◽

2021 ◽

Vol 49 (1) ◽

Author(s):

Aryatara Shilpakar ◽

Mehraj Ansari ◽

Kul Raj Rai ◽

Ganesh Rai ◽

Shiba Kumar Rai

Keyword(s):

Tertiary Care Hospital ◽

Tertiary Care ◽

Polymyxin B ◽

Multidrug Resistant ◽

Confirmatory Test ◽

Clinical Samples ◽

Care Hospital ◽

Gram Negative ◽

Extended Spectrum ◽

Esbl Producers

Abstract Background The existence of multidrug-resistant organisms, including extended-spectrum beta-lactamases (ESBLs), is on rise across the globe and is becoming a severe problem. Knowledge of the prevalence and antibiogram profile of such isolates is essential to develop an appropriate treatment methodology. This study aimed to study the prevalence of Gram-negative isolates exhibiting ESBL at a tertiary care hospital and study their antibiogram profile. Methods A cross-sectional study was conducted at Shahid Gangalal National Heart Centre, Kathmandu, Nepal, from June 2018 to November 2018. A total of 770 clinical samples were collected and identified using the conventional biochemical tests following the Clinical and Laboratory Standard Institute (CLSI) guidelines. Antimicrobial susceptibility testing (AST) was performed using the standardized Kirby-Bauer disk diffusion method. The screening test for ESBL producers was performed as recommended by the CLSI and the confirmatory test was performed phenotypically using the E-test. Results Out of the 92 isolates, 84 (91.3%) were multidrug-resistant, and 47 (51.1%) were found to be potential ESBL producers. Of these, 16 isolates were confirmed ESBL producers by the E-test. Escherichia coli and Klebsiella pneumoniae were the predominant isolates and were also the major ESBL producers. Besides polymyxin B (100% sensitive), meropenem and imipenem showed high efficacy against the ESBL producers. Conclusion Multidrug resistance was very high; however, ESBL production was low. Polymyxin B and carbapenems are the choice of drugs against ESBL producers but should be used only as the last line drugs.

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MULTIPLE ANTIBIOTIC RESISTANCE INDEXING OF NON- FERMENTING GRAM NEGATIVE BACILLI

Asian Journal of Pharmaceutical and Clinical Research ◽

10.22159/ajpcr.2017.v10i6.17717 ◽

2017 ◽

Vol 10 (6) ◽

pp. 78

Author(s):

Bhuvaneshwari Gunasekar

Keyword(s):

Antibiotic Resistance ◽

Tertiary Care ◽

Multidrug Resistant ◽

Diffusion Method ◽

Care Hospital ◽

Multiple Antibiotic Resistance ◽

Antibiotic Resistant ◽

Gram Negative ◽

Mar Index ◽

Surgery Department

Objective: The multiple antibiotic resistance (MAR) indexing and finding Multidrug resistant (MDR) bacteria will help to indicate the origin from high risk of contamination where the antibiotics are often used. Hence this study was carried out to give the MAR index of non-fermenting Gram negative bacilli in a tertiary care hospital which would help our infection control team also.Methods: Drug resistance was tested by Kirby bauer’s disc diffusion method. MAR index was calculated using the formula, a/b (were a= number of antibiotics to which the organism was resistant and b= total number of antibiotics to which the organism was tested).Results: Out of 240 Gram negative non-fermenters isolated, 117 (49%) strains were greater than 0.2 of MAR index, 95(81%) was from in-patient department. 73(62%) were hospitalized for more than 3 days, 44 (38%) was from surgery department. 49(42%) was wound specimen. Out of 117 multiple antibiotic resistant isolates 99 (85%) were MDR isolates.Conclusion: 51% prevalence of isolates >0.2 MAR index shows that the source of contamination can still be brought up down by proper surveillance and management with proper usage of surface and skin disinfectants especially in surgery ward where the MAR index has indicated more usage of antibiotics

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Ecology of Bloodstream Infections and Temporal Trends of Their Antibiograms with Respect to Source and Duration of Incubation: A 5-Year Retrospective Observational Analysis

Journal of Laboratory Physicians ◽

10.1055/s-0040-1714199 ◽

2020 ◽

Vol 12 (01) ◽

pp. 56-67

Author(s):

Amit Banik ◽

Valarie W. Lyngdoh ◽

Elantamilan Durairaj ◽

Anil C. Phukan ◽

Raghavendra Kotal

Keyword(s):

Tertiary Care ◽

Temporal Trends ◽

Bloodstream Infections ◽

Diffusion Method ◽

Blood Collection ◽

Care Hospital ◽

Biochemical Tests ◽

Sensitivity Testing ◽

Disk Diffusion Method ◽

Significant Difference

Abstract Purpose Blood is one of the most important connective tissues of human body. Bloodstream infection can range from inapparent bacteremia till fulminant septic shock with high mortality. Presence of microbes in blood whether continuously, intermittently, or transiently is a grave risk to every organ of body. Culture of blood is a vital tool to diagnose such infections. Drug susceptibility patterns help in rationalizing therapy. Objective The aim of the study is to perform bacteriological analysis and assess drug sensitivity patterns of blood culture isolates and compare in light of other associated variables. Design Retrospective observational study was conducted from January 2009 to December 2013 at a tertiary care hospital at Shillong, India. Blood samples were collected with aseptic guidelines and cultured for 7 days. Growths were identified by standard biochemical tests and subjected to sensitivity testing according to Modified Kirby Bauer disk diffusion method. Data for source of blood collection and duration of incubation were noted and compared. Results A total of 658 (11.2%) pathogens were isolated from 5,867 bacteremia-suspected patient blood specimens. Contamination was observed at the rate of 1.21%. Gram-negative organisms were the predominant pathogens recovered, Klebsiella pneumoniae being the most common. No significant difference was observed between the number of organisms isolated within or beyond 48 hours. Acinetobacter baumannii and K. pneumoniae have significantly higher chances (p < 0.05) of isolation from central line catheters compared with peripheral venipuncture. Conclusion Successful treatment of sepsis depends on early diagnosis and proper antimicrobial therapy. Local knowledge of bacteriological profile and antimicrobial sensitivity patterns helps rationalize empiric treatment strategies.

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Bloodstream infections and trends of antimicrobial sensitivity patterns at Port Blair

Journal of Laboratory Physicians ◽

10.4103/jlp.jlp_50_18 ◽

2018 ◽

Vol 10 (03) ◽

pp. 332-337 ◽

Cited By ~ 1

Author(s):

Amit Banik ◽

Sanjeev H. Bhat ◽

Abhay Kumar ◽

Agnijeet Palit ◽

Kandregula Snehaa

Keyword(s):

Tertiary Care ◽

Bloodstream Infections ◽

The Body ◽

Diffusion Method ◽

Blood Collection ◽

Care Hospital ◽

Biochemical Tests ◽

Sensitivity Testing ◽

Disk Diffusion Method ◽

Antimicrobial Sensitivity

ABSTRACT PURPOSE: Bloodstream infection can range from inapparent bacteremia until fulminant septic shock with high mortality. Microorganisms present in circulating blood whether continuously, intermittently, or transiently are a threat to every organ in the body. Culture of blood is a vital tool to diagnose such infections. Drug susceptibility patterns help in rationalizing therapy. OBJECTIVE: The objective of this study was to perform bacteriological analysis and assess drug sensitivity patterns of isolates from blood stream infections. DESIGN: Retrospective observational study was conducted from May 2015 to February 2017 at a tertiary care hospital, Port Blair, India. Blood samples were collected with aseptic guidelines and cultured for 7 days. Growths were identified using standard biochemical tests and subjected to sensitivity testing according to Modified Kirby–Bauer’s disk diffusion method. Data for the source of blood collection and duration of incubation were noted and compared. RESULTS: A total of 270 (14.24%) pathogens were isolated from 1895 bacteremia suspect patient blood specimens. Contamination was observed at a rate of 1.63%. Gram-positive cocci (60.37%) were predominant organisms recovered followed by Gram-negative Bacilli (36.29%) and Yeasts (3.33%). Staphylococcus aureus, CoNS, and Acinetobacter spp. were the primary pathogens isolated. Aminoglycosides, carbapenems, and glycopeptides were the most effective drugs for treating bacteremia. CONCLUSIONS: Successful treatment of sepsis depends on early diagnosis and proper antimicrobial therapy. Local knowledge of bacteriological profile and antimicrobial sensitivity patterns helps rationalize empiric treatment strategies.

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Salmonella isolates’ serotypes and susceptibility to commonly used drugs at a tertiary care hospital in Riyadh, Saudi Arabia

The Journal of Infection in Developing Countries ◽

10.3855/jidc.1805 ◽

2011 ◽

Vol 6 (06) ◽

pp. 478-482 ◽

Cited By ~ 9

Author(s):

Ali Mohammed Somily ◽

Samina Bashir Sayyed ◽

Hanan Ahmed Habib ◽

Abdulaziz Saleh Al-Khattaf ◽

Fawzia Eida Al Otabi ◽

...

Keyword(s):

Saudi Arabia ◽

Nalidixic Acid ◽

Tertiary Care ◽

University Hospital ◽

Diffusion Method ◽

Care Hospital ◽

Disk Diffusion Method ◽

Salmonella Infections ◽

Overall Resistance ◽

Resistance Rates

Introduction: Resistance of Salmonella to therapeutic agents currently being used for treatment of Salmonella infections is emerging as a global problem. This study aimed to assess the prevalence of Salmonella serotypes and their susceptibility patterns to commonly used drugs for treatment of Salmonella infections including quinolones. Correlation between nalidixic acid susceptibility of these isolates and their ciprofloxacin minimum inhibitory concentrations was also sought. Methodology; Salmonella isolates (n=213) were collected between January 2007 and May 2009 at King Khalid University Hospital in Riyadh, Saudi Arabia. The isolates were serotyped and their susceptibilities to commonly used first-line anti-Salmonella drugs (ampicillin, ceftriaxone, trimethoprim/sulfamethoxazole, nalidixic acid and ciprofloxacin) were determined using the automated Microscan system, the Kirby-Bauer disk diffusion method, and E-test. Results: The most frequently detected serotype was D1 (37%) followed by the serotypes, B (24%) and C1 (11%). Non-typable Salmonella isolates detected using available conventional Salmonella anti-sera were (11%). Overall resistance rates to nalidixic acid, ampicillin, trimethoprim/sulfamethoxazole and ceftriaxone were 99/213 (46%), 43/213 (20%), 34/213 (16%) and 7/213 (3%), respectively. Of the total isolates, 117 (55%) had a ciprofloxacin MIC of < 0.125 µg/ml and among these 105 (90%) were susceptible to nalidixic acid. The remaining 96 (45%) isolates had a ciprofloxacin MIC of ≥ 0.125 µg/ml and among them, 83 (86.5%) were resistant to nalidixic acid. Conclusions: The majority of Salmonella isolates in this study were non-typhi serotypes. Significantly higher proportions of Salmonellae were resistant to nalidixic acid and ciprofloxacin and a vast majority of nalidixic acid resistant organisms exhibited decreased susceptibility to ciprofloxacin.

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